In principle, gifting something automatically erodes its value by 10 to 30 percent. But when asked how much they'd be willing to pay for the gift, people want more money now. This is classic behavioral economics at play. Once we own something, we tend to overvalue it. There's a different sort of happiness associated with receiving a gift. So while giving gifts might be economically stupid, sentimentally, it may be the best thing in the world.